"The Wrecking Crew" (sometimes referred to as "the Clique" and "the First Call Gang") was a loose-knit circle of Los Angeles' top studio session musicians whose services were constantly in demand during their heyday in the 1960s and early 1970s. In varying configurations, often anonymously, they backed dozens of popular acts on numerous top-selling hits of the era. They are considered one of the most successful recording session units in music history. The group's ranks began to materialize in the late 1950s, but in the early 1960s they fully coalesced into what became their most recognizable form when they became the de facto "house band" for Phil Spector, sometimes referred to as the Phil Spector Wall of Sound Orchestra, playing on many of the hits that he produced at the time, by acts such as the Crystals, the Ronettes, and later the Righteous Brothers and Ike and Tina Turner, contributing to Spector's characteristic "wall of sound" production style.